TIN TINElement OGC® Geography Markup Language (GML) - Extended schemas and encoding rules

24 Copyright © 2012 Open Geospatial Consortium

8.3 TriangulatedSurface

element name=TriangulatedSurface type=gml:SurfaceType substitutionGroup=gml:Surface gmltin:TriangulatedSurface implements ISO 19107 GM_TriangulatedSurface see D.2.3.4 and ISO 19107:2003, 6.4.37. A triangulated surface is a polyhedral surface that is composed only of triangles. There is no restriction on how the triangulation is derived. gml:patches encapsulates the triangles of the triangulated surface. All patches shall be simple triangle patches.

8.4 SimpleTrianglePatch

complexType name=SimpleTrianglePatchType complexContent extension base=gml:AbstractSurfacePatchType sequence choice choice minOccurs=3 maxOccurs=3 element ref=gml:pos element ref=gml:pointProperty choice element ref=gml:posList choice sequence attribute name=interpolation type=gml:SurfaceInterpolationType fixed=planar extension complexContent complexType element name=SimpleTrianglePatch type=gmltin:SimpleTrianglePatchType substitutionGroup=gml:AbstractSurfacePatch gmltin:SimpleTrianglePatch is based upon the pattern used in the GML 3.3 SimpleTriangle, rather than the GML 3.2 Triangle. A gmltin:SimpleTrianglePatch is a surface patch that is defined by a set of three points. The points shall be coplanar and the resultant simple triangle uses planar interpolation in its interior. The boundary of simple triangle patch can be obtained by constructing a gml:LinearRing, defined by four coordinate tuples representing the three points such that the first point is repeated as the last point, with linear interpolation between the points. interpolation is fixed to planar, i.e. an interpolation shall return points on a single plane. The boundary of the patch shall be contained within that plane.

8.5 TIN

complexType name=TINType complexContent extension base=gml:SurfaceType sequence Copyright © 2012 Open Geospatial Consortium 25 element name=tinElement type=gmltin:TINElementPropertyType minOccurs=0 maxOccurs=unbounded element name=maxLength type=gml:LengthType minOccurs=0 sequence extension complexContent complexType element name=TIN type=gmltin:TINType substitutionGroup=gmltin:TriangulatedSurface gmltin:TIN is a triangulated surface that uses the Delaunay algorithm or a similar algorithm complemented with consideration of constraints defined by TIN Elements gmltin:tinElements and possibly a maximum length of triangle sides gmltin:maxLength. The set of the positions three or more used as posts for this TIN corners of the triangles in the TIN are specified either in TIN Element control points or group spots. gmltin:TIN implements ISOIEC 13249-3 ST_TIN see ISOIEC FCD 13249-3 8.6.1 ST_TIN Type which extends ISO 19107 see ISO 19136:2007 D.2.3.4 and ISO 19107:2003, 6.4.37.

8.6 TINElement

complexType name=TINElementType complexContent extension base=gml:AbstractFeatureType sequence element name=elementType type=gmltin:TINElementTypeType element name=elementID type=integer minOccurs=0 element name=elementTag type=string minOccurs=0 element name=elementGeometry type=gml:GeometryPropertyType sequence extension complexContent complexType element name=TINElement type=gmltin:TINElementType substitutionGroup=gml:AbstractObject gmltin:TINElement implements ISOIEC 13249-3 ST_TINElement see ISOIEC FCD 13249-3 15.1.1 ST_TINElement Type. It specifies elements associated with a TIN which can be: 1 constraints boundary, break line, soft break, control contour, break void, drape void, void, hole, stop line applied to a TIN surface after the initial Delaunay triangulation which modify the surface, 2 points random points, group spots which are the vertices of simple triangles that define the TIN surface or vertices of constraints, or 3 user-defined. The gmltin:elementType property specifies the type of TIN element. Allowable values are specified by the gmltin:TINElementTypeType codelist. 26 Copyright © 2012 Open Geospatial Consortium The gmltin:elementID property allows for an optional integer value to numerically identify the TIN element. The gmltin:elementTag property allows for an optional string value to alphanumerically identify the TIN element. The gmltin:elementGeometry property specifies the geometry of the TIN element. The allowable geometry type is dependent upon the value of the gmltin:elementType: - random points and group spot TIN elements shall have a 3D gml:MultiPoint geometry - boundary, break void and void TIN elements shall have a 3D gml:Polygon geometry - drape void and hole TIN elements shall have a 2D or 3D gml:Polygon geometry - break line, soft break and control contour TIN elements shall have a 3D gml:LineString geometry - stop line TIN elements shall have a 2D or 3D gml:LineString geometry - for a user-defined TIN element, the choice of gml:GeometryPropertyType shall be user-defined.

8.7 TINElementPropertyType